Codes po171/ and po175

2003 FORD F-150

200,000 MILES • 4.2L • V6 • 2WD • MANUAL

JASONR#24

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po171-Bank 1 too lean and po175-Bank 2 too rich. The truck has very low if any acceleration. I have to help shifting gears by pressing and releasing the gas pedal. When at idle stop, you can smell exhaust fumes.
Hopefully someone has the answer.

Jul 19, 2021 at 7:33 AM

SQM

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6,383 POSTS

Hello,

This issue can happen for several reasons.
It could be a defective MAF sensor, faulty fuel pressure regulator, restricted fuel line, air leak after the MAF sensor, etc. It could even be for a vacuum leak.

I have attached a diagnostics chart for the P0171 and P0175 code for your reference.
Please have a look at and should be able to narrow down the issue.

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing

Please let me know of any questions.

Thank you.

Images (Click to enlarge)

Jul 19, 2021 at 9:59 AM